Views: 262,434 Homepage | Main | Rules/FAQ | Memberlist | Active users | Last posts | Calendar | Stats | Online users | Search 09-26-18 10:32 AM
Guest:

0 users reading the writable VCount shit | 1 bot

Main - Development - the writable VCount shit New reply


StapleButter
Posted on 05-05-17 12:44 PM (rev. 2 of 05-05-17 12:54 PM) Link | #144
finding dump


* writing to VCOUNT (val < current) makes the frame last longer
* VCOUNT write is applied at the next scanline
* VCOUNT can be written during display (!!)
** doing so screws up display: the 2D GPU uses the new VCOUNT value, but the LCDs keep going from the old value
** I don't want to imagine what that does to the 3D GPU or HDMA
** and it can likely cause VBlank/VMatch IRQs to trigger again
** the GPU can't go past scanline 191 (if you abuse VCOUNT write to make it skip forward) -- further scanlines are filled white

* it's writable from either CPU


Main - Development - the writable VCount shit New reply

Page rendered in 0.011 seconds. (2048KB of memory used)
MySQL - queries: 28, rows: 73/73, time: 0.008 seconds.
[powered by Acmlm] Acmlmboard 2.064 (2018-07-20)
© 2005-2008 Acmlm, Xkeeper, blackhole89 et al.